Steinhoff M M, Lee L H, Jakschik B A
Biochim Biophys Acta. 1980 Apr 18;618(1):28-34. doi: 10.1016/0005-2760(80)90050-8.
It has been shown that the major cyclooxygenase product in rat basophilic leukemia (RBL-1) cells and in normal rat mast cells is prostaglandin D2. In RBL-1 cells, prostaglandin D2 is isomerase activity was found in the 150 000 X g microsomal pellet as well as the supernatant fraction. Incubation of RBL-1 microsomes with arachidonic acid without cofactors yielded 17.5 +/- 2% prostaglandin E2 and 9.1 +/- 1.4% prostaglandin D2. The cyclooxygenase activity was enhanced (25%) by epinephrine and the addition of reduced glutathione led to a marked increase in prostaglandin D2 synthesis (3-fold). Incubations with arachidonic acid, glutathione and epinephrine gave the maximum conversion to prostaglandin D2, yielding 7 +/- 0.4% prostaglandin E2 and 35.6 +/- 3.5% prostaglandin D2. Incubations with [14C]prostaglandin H2 to bypass cyclooxygenase confirmed the presence and glutathione dependence of the prostaglandin D2 isomerase in the microsomal fraction and also revealed the presence of the same enzyme in the 150 000 X g supernant. In contrast to RBL-1 cells, incubations of microsomes and supernatant from normal rat mast cells with [14C]-arachidonic acid and [14C]prostaglandin H2 localized the prostaglandin D2 isomerase activity in the soluble fraction. Similar to the enzyme in the RBL-1 cells, the mast cell enzyme was glutathione dependent.
已表明，大鼠嗜碱性白血病（RBL - 1）细胞和正常大鼠肥大细胞中的主要环氧化酶产物是前列腺素D2。在RBL - 1细胞中，前列腺素D2异构酶活性在150000×g微粒体沉淀以及上清液部分中均有发现。将RBL - 1微粒体与花生四烯酸在无辅助因子的情况下孵育，产生了17.5±2%的前列腺素E2和9.1±1.4%的前列腺素D2。肾上腺素可增强环氧化酶活性（25%），添加还原型谷胱甘肽可导致前列腺素D2合成显著增加（3倍）。用花生四烯酸、谷胱甘肽和肾上腺素孵育可使转化为前列腺素D2的量达到最大，产生7±0.4%的前列腺素E2和35.6±3.5%的前列腺素D2。用[14C]前列腺素H2孵育以绕过环氧化酶，证实了微粒体部分中前列腺素D2异构酶的存在及其对谷胱甘肽的依赖性，同时也揭示了在150000×g上清液中存在相同的酶。与RBL - 1细胞不同，用[14C] - 花生四烯酸和[14C]前列腺素H2孵育正常大鼠肥大细胞的微粒体和上清液，将前列腺素D2异构酶活性定位在可溶性部分。与RBL - 1细胞中的酶类似，肥大细胞中的酶也依赖于谷胱甘肽。
